In many transmitter, receiver or transceiver applications, a local oscillator (LO) signal is used, for instance, for up-mixing or down-mixing a signal to be transmitted or received, respectively. In many of these applications, different transmission techniques, for instance different radio-based transmission techniques, are used to transmit, receive or exchange data. For instance, mobile devices operating in a cellular network may not only communicate inside the specific network, but also transmit, receive or exchange data using other, only locally available radio-based transmission access points.
In some of these applications, the different transmission technologies available may even be used simultaneously, for instance, to transmit, receive or exchange data, for synchronizing calendars, notes or other pieces of information, while at the same time programs, applications or other data may be downloaded from a server. Moreover, in the case of cellular phones, during transmitting, receiving or exchanging data, telephone conversations may be held.
Since many of these different transmission technologies operate in different frequency bands or at different wavelengths, several local oscillator signals may have to be provided having different frequencies, sometimes even at the same time. Implementing several oscillator circuits providing different local oscillator signals simultaneously may cause unwanted coupling effects and may result in comparably large and complex implementations. DTC-based (DTC=digital-to-time converter) implementations may be used, which may rely on a smaller number of oscillator circuits. However, with increasing operation frequencies, the complexity and accuracy of control circuits for controlling the digital-to-time converters may become more complex due to the higher operation frequencies necessary to operate them.